1. Field of the Invention
This invention relates to an agricultural rake device. In one example, the invention relates to a locking device for a bifold or V-rake type. In an exemplary embodiment, the bifold rake is used for raking grass or hay.
2. Description of the Related Art
Agricultural rakes are used to form windrows from cut crops, such as, for example, hay, straw, corn fodder, and grasses. It is a typical agricultural process to cut these crops, rake or merge them into windrows where additional drying may occur, collect and store the crops, and subsequently feed the crops to livestock.
Modern power equipment for raking cut forage employs rotating tined wheels and particularly banks of rotating tined wheels that are moved through a field of cut forage to form windrows. These banks of wheel rakes can be quite wide to reduce both the time and number of passes required to rake a field. Because of the wide widths employed by rakes, they typically will have pivot points on each rake arm in order to fold to a narrower width for transport. Wide rakes thereby offer a potential time and cost savings to agriculture and enhance the raking process to best utilize favorable weather conditions, or to maximize the capacity utilization of the next piece of hay raking equipment.
The wide rakes require longer rake arms to support the banks of tined wheels required for efficient raking. Each rake arm includes a number of tined rake wheels which contact the ground in a operating position, and serve to rake crop material into a center windrow while being pulled through a field of cut hay or alfalfa. These long rake arms, of which there are two in so-called “bifold” rakes, can be heavy and cumbersome both in operation and in transport. While in operation, the bifold rake arms are normally spread in a “V” shape with the open end of the “V” facing forward in the direction of travel. When in a transport position, the machine must be configured to be much narrower than when the machine is in a raking, i.e., operating position. Therefore, the rake arms must pivot and/or fold in order to make the machine narrow for transport.
When the rake arms are folded for transport, it is preferred to provide a transport locking mechanism for holding the rake arms in this folded position so that they cannot unfold unexpectedly. One method is to hydrostatically lock the hydraulic cylinders responsible for moving the rake arms in and out of transport position. A hydraulic locking mechanism such as a quarter turn valve, ball valve, or pilot check valve can be used to stop the flow of hydraulic fluid to and from the cylinder. These valves are either attached to the cylinder port, or anywhere along the hydraulic hose which extends to the hydraulic source or tractor valve. This method relies on the integrity of the hydraulic system, and the rake arms can open unexpectedly upon a failure of the cylinder, hoses, or valve. In other words, if hydraulic pressure is lost, the locking mechanism may fail.
A second method of locking the rake arms for transport is to provide mechanical pins which connect the rake arms to a portion of the rake frame while in transport position. These pins can be inserted and removed manually by the operator, or spring loaded and attached to a rope or chain for operation from the cab of the tractor. This method is requires direct interaction from the operator to lock or unlock the arms. Serious damage can be caused if the operator forgets to remove the pins before trying to hydraulically operate the rake arms.
An alternative version of the mechanical pin method is to provide a dedicated bar or pipe extending in a direction transverse to the direction of travel of the rake. The pipe has holes on each end and is connected to holes on the arms by the operator via pins. This method can be difficult inasmuch as the holes in the pipe may not line up with the holes in the rake arms, and the operator is required to force the pipe into position.